The primary objective of this proposal is to correlate pharmacological effects of dopamine and norepinephrine with plasma levels. To accomplish this a specific, sensitive and simple assay for dopamine and norepinephrine will be developed. Radioimmunoassay offers such a potential. Antibodies will be prepared against dopamine and norepinephrine by conjugating them to methylated bovine serum albumin. The immunogen (100 micrograms in Freund's complete adjuvant will be injected into rabbits. The specificity of the antibody will be determined by testing a series of metabolites and analogs. The anti-dopamine and anti-norepinephrine antibodies may provide sensitive and specific methods for the analysis of therapeutic levels of these catecholamines in biological fluids. The radioimmunoassays of dopamine and norepinephrine will be used to determine the levels of these catecholamines in patients with certain pathological conditions (myocardial infarction, Parkinson's disease, etc.). Furthermore, attempts will be made to label these antibodies with gamma emitting radionuclides. These antibodies may serve as potential scanning agents for the adrenal medulla.